ipympl 0.8.2 - ginput() does not work on Jupyterlab / returns an empty array

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**Describe the bug**
I should be able to select data points from a figure and then red crosses are supposed to appear after clicking with the mouse, but nothing happens, an empty array is returned and the figures only appear after the timeout of ginput().

**Expected behavior**
Figure pops up and I can click with the mouse on the figure to select data points. An array will be generated

**To Reproduce**

```
%matplotlib widget

import matplotlib.pyplot as plt
import numpy as np
t = np.arange(10)

plt.plot(t, np.sin(t))

plt.title('matplotlib.pyplot.ginput()\
function Example', fontweight ="bold")

print("After 3 clicks :")
x = plt.ginput(3)
print(x)

plt.show()

```
**My Platform**

Firefox on Arch Linux, latest version after system update.
I tested it on Jupyterlab, I did not test it on Jupyter-notebook.

Start by running the issue's minimal reproduction with the `%matplotlib widget` backend in JupyterLab on Firefox. Investigate why `plt.ginput(3)` returns an empty array and the figure appears only after the timeout; done means mouse clicks produce the expected coordinates and red cross markers.

Written by the indexing model from the issue text.